Open system heat exchange catheters and methods of use

ABSTRACT

Various embodiments of open system heat exchange catheters and methods of use are disclosed. The various catheters can be used with various ablative surgical devices. One specific exemplary use is in conjunction with cryosurgical probes involving ablation of the prostate, in which the integrity of the urethra is desired to be maintained. Other uses involve various heating ablative devices. In one embodiment an injection tube assembly is used to provide heat exchange fluid through the urethra to the bladder where it is then expelled via a suprapubic suction tube. In other embodiments a coaxial tube assembly is utilized which defines a passageway for either expelling the bladder fluid or for providing access to an endoscope. In other embodiments a double lumen assembly is utilized that defines a passageway for expelling bladder fluid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to urological warming and cooling devicesand more particularly to a method of warming or alternatively coolingthe urethra of a patient during ablative surgery.

2. Description of the Related Art

Cryosurgical probes are used to treat a variety of diseases. Thecryosurgical probes quickly freeze diseased body tissue, causing thetissue to die after which it will be absorbed by the body, expelled bythe body or sloughed off. Cryothermal treatment is currently used totreat prostate cancer and benign prostate disease, breast tumors andbreast cancer, liver tumors and liver cancer, lung tumors, kidneytumors, bone tumors, glaucoma and other eye diseases. Cryosurgery isalso proposed for the treatment of a number of other diseases.

The use of cryosurgical probes for cryoablation of the prostate isdescribed in Onik, Ultrasound-Guided Cryosurgery, Scientific American at62 (January 1996) and Onik, Cohen, et al., Transrectal Ultrasound-GuidedPercutaneous Radial Cryosurgical Ablation Of The Prostate, 72. Cancer1291 (1993). In this procedure, generally referred to as cryoablation ofthe prostate, several cryosurgical probes are inserted through the skinin the perineal area (between the scrotum and the anus), which providesthe easiest access to the prostate. The probes are pushed into theprostate gland through previously placed cannulas. Placement of theprobes within the prostate gland is visualized with an ultrasoundimaging probe placed in the rectum. The probes are quickly cooled totemperatures typically below −120° C. The prostate tissue is killed bythe freezing, and any tumor or cancer within the prostate is alsokilled. The body absorbs some of the dead tissue over a period ofseveral weeks. However, other necrosed tissue may slough off and passthrough the urethra, often causing undesirable blockage. Thus, it isoften desirable to avoid cryoinjury to the urethra during cryoablationof the prostate. This may be done by placing a warming catheter in theurethra and continuously flushing the catheter with warm fluid to keepthe urethra from freezing.

Devices for warming the urethra have been available for quite some time.In 1911, U.S. Pat. No. 1,011,606 issued for an “Appliance For SubjectingPortions Of The Human System To Heat Or Cold.” This device was a coaxialdual lumen catheter intended for the application of therapeutic coolingor heating to the urethra and bladder. Devices for warming other bodyparts have also been proposed, such as Grams, Ear Probe For Use InClosed-Loop Caloric Irrigation, U.S. Pat. No. 4,244,377 (Jan. 13, 1981),which shows a coaxial dual lumen cannula intended for the application oftherapeutic heating inside the ear.

Baust, et al., Closed Circulation Tissue Warming Apparatus and Method ofUsing the Same in Prostate Surgery, U.S. Pat. No. 5,437,673 (Aug. 1,1995), and related publications, illustrate use of a urethral warmingcatheter which is used to protect the urethra from cryothermal damageduring cryosurgical treatment of the prostate for benign prostatehyperplasia. The Baust patent discloses a coaxial three lumen catheterin which warm saline passes through the outside lumen, returns through acoaxial second lumen, while the third lumen is a urinary drainage lumencentrally disposed within the other two lumens. The catheter is used toheat the urethra while the prostate is being frozen with cryosurgicalprobes.

Eshel, Technique for Localized Thermal Treatment of Mammals, U.S. Pat.No. 5,257,977 (Nov. 2, 1993) shows a catheter which delivers heatedsaline flow to provide therapeutic hyperthermia treatment of theprostate. Like the Baust patent, Eshel shows a three lumen catheter withcentrally located urinary drainage lumen.

Still other devices have been described for importing fluid into thebody and allowing a means for removing fluid from the body. One suchdevice is described in Schossow, Endotracheal Tube, U.S. Pat. No.3,087,493 (Apr. 27, 1960). Schossow describes a device employed tointubate the human trachea, such device connected with ducts and/ortubes outside the patient for the purpose of, for example, drawing offfrom the patient's respiratory tract undesirable liquids and/orintroducing beneficial liquids into the trachea. The device consists ofan outer tube, which fits inside the patient's trachea, and a twolayered inner tube. The lumen of the inner tube is open to be connectedwith devices or ducts through which suction may be applied or fluidsinjected into the trachea. The distal portion of the inner tube isvented with ports or openings which create a “sprinkler” effect insidethe tube. Schossow does not suggest use as a urethral warming catheterduring cryoablation of the prostate.

During cryoablation, the prostate tissue is killed by freezingtemperatures in the cryogenic temperature range, typically −120° C. andbelow. The hot fluid used for the warming catheter is supplied at about30° C. to 50° C. Warm fluid is pumped through the urethral warmingcatheter, such as the catheter described in Baust. As the warm fluidtravels the length of the urethral catheter disposed within thecryosurgically cooled urethra, it is cooled by the surrounding freezingtissue. By the time the hot water has traveled from the bladder necksphincter to the external sphincter, it has been significantly cooled bythe surrounding frozen prostate. As a result, the urethral tissue nearthe bladder neck sphincter (near the hot water outlet) is heated morethan the urethral tissue near the external sphincter, creating a strongthermal gradient in the prostatic urethra and an uneven heating effect.By the time the hot water reaches the external sphincter, it may havelost so much heat to the upper region of the urethra that it is not warmenough to protect the external sphincter from freezing. In order for thetissue at the bladder neck sphincter to be adequately warmed, hotterwater must be pumped in, risking urethral damage due to scalded tissue,or more water must be pumped at higher rates and pressures, increasingthe material requirements of the hot water supply system and the warmingcatheter.

U.S. Pat. No. 6,017,361, issued to Mikus et al, entitled UrethralWarming Catheter, discloses an improved method and means for maintainingthe temperature of urethral tissues during cryoablation of the prostategland and thereby eliminates or reduces the sloughing of dead cells intothe urethra. Diffuser holes or ports, much like a “sprinkler,” aredrilled into the inner tube of the warming catheter. The holes create anadvantage over the prior art of achieving improved uniformity of fluidflow and temperature, utilizing a lower initial temperature andresulting in a more even application of thermal treatment to theurethral tissues. The apparatus may find additional utility in otherareas of surgery where thermal treatment or maintenance of tissues isrequired with or without the capability of drainage.

SUMMARY OF THE INVENTION

The present invention includes various embodiments of open system heatexchange catheters and methods of use. The various catheters can be usedwith various ablative surgical devices. One specific exemplary use is inconjunction with cryosurgical probes involving ablation of the prostate,in which the integrity of the urethra is desired to be maintained. Otheruses involve use with various heating ablative devices.

In one main aspect, the method for providing heat exchange with theurethra involves inserting a suprapubic suction tube into the bladder ofa patient. At least one ablative surgical device is inserted into aprostate region of the patient. An injection tube assembly insertedthrough the patient's urethra and into the bladder. Heat exchange fluidis delivered through the injection tube assembly during operation of theat least one ablative surgical device, the heat exchange fluid isdelivered into the bladder. The suction tube expels bladder fluid fromthe bladder during the delivering of heat exchange fluid through theinjection tub assembly. The bladder fluid includes the heat exchangefluid. The urethra is warmed or alternatively cooled by the heatexchange fluid to preserve living tissue thereof.

In other embodiments, a coaxial tube assembly is used. With such anarrangement the coaxial portion can be used to define a path for thereturn of bladder fluid. This obviates the use of a suprapubic suctiontube in providing this function. Alternatively, the use of a coaxialportion allows access for an endoscope.

In another embodiment, a double lumen tube assembly is utilized. The useof a double lumen tube assembly also obviates the need of a suprapubicsuction tube by defining a path for the return of bladder fluid.

These systems are open systems inasmuch as fluid from the heat exchangecatheters is not isolated from bladder fluid. Instead, it is mixed withthe bladder fluid and then expelled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the lower abdominal portion of thehuman body with a first embodiment of the heat exchange catheter inplace, the first embodiment comprising an open tube, being utilized witha suprapubic suction tube.

FIG. 2 is a cross-sectional view of a second embodiment of the heatexchange catheter in which a coaxial portion allows the heat exchangecatheter to be used as both an inlet and an outlet for heat exchangefluid.

FIG. 3 is a cross-sectional view of a third embodiment of the heatexchange catheter in which a coaxial portion provides for theintroduction of an endoscope, the heat exchange catheter being utilizedwith a suprapubic suction tube.

FIG. 4 is a cross-sectional view of a fourth embodiment of the heatexchange catheter in which a double lumen tube assembly providesutilization of the device as both an inlet and an outlet for heatexchange fluid.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the characters of reference markedthereon, FIG. 1 illustrates a first preferred method of warming aurethra 10 of a patient 12 during ablative surgery in accordance withthe principles of the present invention. In this method a suprapubicsuction tube 14 is inserted into the bladder 16 of the patient 12.Ablative devices 18 are inserted into the prostate region 20 of thepatient 12. An injection tube assembly, designated generally as 22, isinserted through the patient's urethra 10 and into the bladder 16.Warming fluid is delivered through the injection tube assembly 22 duringoperation of the ablative surgical devices 18. The warming fluid isdelivered into the bladder 16. The suction tube 14 is operated to expelbladder fluid from the bladder 16 during the delivering of warming fluidthrough the injection tub assembly 22, the bladder fluid including thewarming fluid. The urethra is warmed by the warming fluid to preserveliving tissue thereof.

The ablative devices are preferably cryosurgical probes such asmanufactured and marketed by Endocare, Inc., of Irvine, Calif. Thefigure shows use of six cryosurgical probes 18 as well as fourtemperature probes 19. Alternatively, other ablative devices may beused, for example, radio frequency electrodes, laser fibers, microwavecatheters, high-intensity focused ultrasound. In such instances the heatexchange fluid is cool so as to prevent the urethra from the heating bythe ablative elements.

In this first embodiment illustrated, the injection tube assemblyincludes a single tube assembly including an insertable injection tube24, a connector 26 and a source tube 28. The tubes 24 and 28 arepreferably formed of a flexible material such as various plastics,including, for example, polyethelene. The connector 26 is a suitablerigid material such as polycarbonate.

Although not shown the injection tube assembly 22 receives warming fluidfrom a pump and warmer, which are, in turn, connected to a reservoir.

Referring now to FIG. 2 another embodiment of a warming catheter, i.e.injection tube assembly, is illustrated, designated generally as 30, inwhich a first section of the injection tube assembly provides deliveryof warming fluid and a second section expels bladder fluid. In thisembodiment, the warming catheter includes a single tube inlet 32. Acoaxial portion 34 includes an inner coaxial tube 36 and an outercoaxial tube 38. The outer coaxial tube 38 is in fluid communicationwith the inlet 32 and discharges warming fluid into the bladder. Theinner coaxial tube 36 introduces bladder fluid from the bladder. Anoutlet 40 is preferably a single tube that is in fluid communicationwith the inner tube 36. A connector 42 connects the inlet 32, thecoaxial portion 34 and the outlet 40.

During use, warming fluid is delivered through the inlet 32, through theouter coaxial tube 38, thus warming the urethra, discharged to thebladder, and mixed with bladder fluid. Bladder fluid is directed throughthe inner coaxial tube 36 and through the outlet 40. As with theprevious embodiment this system is an open system, that is, the fluidfrom the warming catheter 30 is discharged freely into the bladder.

Referring now to FIG. 3, another embodiment of the present invention isillustrated, designated generally by 44, in which the injection tubeassembly includes a co-axial portion; however, in this embodiment, thisprovides access for an endoscope. As in the previous embodiment theinjection tube assembly 44 includes a warming fluid inlet comprising asingle tube 46. A coaxial portion 48 includes an inner coaxial tube 50and an outer coaxial tube 52. The outer coaxial tube 52 is in fluidcommunication with the inlet 46 and discharges warming fluid into thebladder. However, the inner coaxial tube 50 does not introduce bladderfluid from the bladder. Instead, it retains a distal portion of anendoscope 54. An endoscope inlet 54 is preferably a single tube that isin communication with the inner tube 50 so that the endoscope inletcontains a proximal portion of the endoscope and the inner coaxial tuberetains a distal portion of the endoscope. A connector 56 connects theinlet 46, the coaxial portion 48 and the endoscope inlet 54.

During use, warming fluid is delivered through the inlet 46, through theouter coaxial tube 52, thus warming the urethra, discharged to thebladder, and mixed with bladder fluid. Bladder fluid is directed througha suprapubic suction tube. The inner coaxial tube 50 and the endoscopeinlet 54 cooperate to provide access to an endoscope 58. As with theprevious embodiments this system is an open system, that is, the fluidfrom the warming catheter 30 is discharged freely into the bladder.

Referring now to FIG. 4, another embodiment of the present invention isillustrated in which the injection tube assembly comprises a doublelumen tube assembly, designated generally as 60. The double lumen tubeassembly 60 includes a single tube inlet 62. A double lumen portion 64includes a first fluid passageway 66 and a second fluid passageway 68.The first fluid passageway 62 is in fluid communication with the inlet62 and discharges warming fluid into the bladder. The second fluidpassageway 68 introduces bladder fluid from the bladder and directs itthrough a single tube outlet 70. A connector 72 is preferably used toconnect the double lumen portion 64 with the inlet 62 and outlet 70.

Although the examples discussed above refer to the use of a warmingfluid it is understood that if the ablative devices are for heatingrather than for cooling, the heat exchange fluid would be a coolingfluid.

Thus, while the preferred embodiments of the devices and methods havebeen described in reference to the environment in which they weredeveloped, they are merely illustrative of the principles of theinvention. Other embodiments and configurations may be devised withoutdeparting from the spirit of the invention and the scope of the appendedclaims.

1. (canceled)
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. (canceled) 6.A method for warming the urethra of a patient during ablative surgery,comprising the steps of: a) inserting at least one ablative surgicaldevice into a prostate region of the patient; b) inserting an injectiontube assembly through the patient's urethra and into the bladder; c)delivering warming fluid through a first section of said injection tubeassembly during operation of said at least one ablative surgical device,said warming fluid being delivered into the bladder; and, f) operating asecond section of said injection tube assembly to expel bladder fluidfrom the bladder during said delivering of warming fluid through saidinjection tube assembly, said bladder fluid including said warmingfluid, wherein said urethra is warmed by said warming fluid to preserveliving tissue thereof.
 7. The method of claim 6, wherein said step ofinserting an injection tube assembly comprises inserting a co-axial tubeassembly, said co-axial tube assembly comprising: a) an inlet comprisinga single tube; b) a coaxial portion, comprising: i) an inner coaxialtube; and ii) an outer coaxial tube, said inner coaxial tube and outercoaxial tube being coaxial, said outer coaxial tube being in fluidcommunication with said inlet and for discharging said warming fluidinto the bladder, said inner coaxial tube for introducing bladder fluidfrom said bladder; c) an outlet comprising a single tube, said outletbeing in fluid communication with said inner tube; and, d) a connectorfor connecting said inlet, said coaxial portion and said outlet, whereinduring use, warming fluid is delivered through said inlet, through saidouter coaxial tube thus warming said urethra, discharged to the bladder,and mixed with bladder fluid, and wherein bladder fluid is directedthrough said inner coaxial tube and through said outlet.
 8. The methodof claim 6, wherein said step of inserting an injection tube assemblycomprises inserting a double lumen tube assembly, said double lumen tubeassembly comprising: a) an inlet comprising a single tube; b) a doublelumen portion, comprising: i) a first fluid passageway; and ii) a secondfluid passageway, said first fluid passageway being in fluidcommunication with said inlet and for discharging said warming fluidinto the bladder, said second fluid passageway for introducing bladderfluid from said bladder; c) an outlet comprising a single tube, saidoutlet being in communication with said second fluid passageway, whereinduring use, warming fluid is delivered through said inlet, through saidfirst fluid passageway thus warming said urethra, discharged to thebladder, and mixed with bladder fluid, and wherein bladder fluid isdirected through said second passageway and through said outlet.
 9. Amethod for warming the urethra of a patient during ablative surgery,comprising the steps of: a) inserting a suprapubic suction tube into thebladder of a patient; b) inserting at least one ablative surgical deviceinto a prostate region of the patient; c) inserting an injection tubeassembly through the patient's urethra and into the bladder, saidinjection tube assembly comprising: i. a warming fluid inlet comprisinga single tube; ii. a coaxial portion comprising:
 1. an inner coaxialtube; and
 2. an outer coaxial tube, said inner coaxial tube and outercoaxial tube being coaxial, said outer coaxial tube being in fluidcommunication with said warming fluid inlet and for discharging saidwarming fluid into the bladder, said inner coaxial tube for retaining adistal portion of an endoscope; iii) an endoscope inlet comprising asingle tube, said endoscope inlet for containing a proximal portion ofan endoscope; and, iv) a connector for connecting said warming fluidinlet, said coaxial portion and said endoscope inlet; d) deliveringwarming fluid through said inlet of said injection tube assembly duringoperation of said at least one ablative surgical device, said warmingfluid being delivered into the bladder; and, e) operating said suctiontube to expel bladder fluid from the bladder during said delivering ofwarming fluid through said injection tub assembly, said bladder fluidincluding said warming fluid, wherein said urethra is warmed by saidwarming fluid to preserve living tissue thereof.
 10. The method of claim9, further comprising the step of inserting an endoscope into saidendoscope inlet.
 11. (canceled)
 12. (canceled)
 13. (canceled) 14.(canceled)
 15. (canceled)
 16. A method for cooling the urethra of apatient during ablative surgery, comprising the steps of: a) insertingat least one ablative surgical device into a prostate region of thepatient; b) inserting an injection tube assembly through the patient'surethra and into the bladder; c) delivering cooling fluid through afirst section of said injection tube assembly during operation of saidat least one ablative surgical device, said cooling fluid beingdelivered into the bladder; and, d) operating a second section of saidinjection tube assembly to expel bladder fluid from the bladder duringsaid delivering of cooling fluid through said injection tube assembly,said bladder fluid including said cooling fluid, wherein said urethra iswarmed by said cooling fluid to preserve living tissue thereof.
 17. Themethod of claim 16, wherein said step of inserting an injection tubeassembly comprises inserting a co-axial tube assembly, said co-axialtube assembly comprising: a) an inlet comprising a single tube; b) acoaxial portion comprising: a. an inner coaxial tube; and b. an outercoaxial tube, said inner coaxial tube and outer coaxial tube beingcoaxial, said outer coaxial tube being in fluid communication with saidinlet and for discharging said cooling fluid into the bladder, saidinner coaxial tube for introducing bladder fluid from said bladder; c)an outlet comprising a single tube, said outlet being in fluidcommunication with said inner tube; and, d) a connector for connectingsaid inlet, said coaxial portion and said outlet, wherein during use,cooling fluid is delivered through said inlet, through said outercoaxial tube thus cooling said urethra, discharged to the bladder, andmixed with bladder fluid, and wherein bladder fluid is directed throughsaid inner coaxial tube and through said outlet.
 18. The method of claim16, wherein said step of inserting an injection tube assembly comprisesinserting a double lumen tube assembly, said double lumen tube assemblycomprising: a) an inlet comprising a single tube; b) a double lumenportion, comprising: i) a first fluid passageway; and ii) a second fluidpassageway, said first fluid passageway being in fluid communicationwith said inlet and for discharging said cooling fluid into the bladder,said second fluid passageway for introducing bladder fluid from saidbladder; c) an outlet comprising a single tube, said outlet being incommunication with said second fluid passageway, wherein during use,cooling fluid is delivered through said inlet, through said first fluidpassageway thus cooling said urethra, discharged to the bladder, andmixed with bladder fluid, and wherein bladder fluid is directed throughsaid second passageway and through said outlet.
 19. A method for coolingthe urethra of a patient during ablative surgery, comprising the stepsof: a) inserting a suprapubic suction tube into the bladder of apatient; b) inserting at least one ablative surgical device into aprostate region of the patient; c) inserting an injection tube assemblythrough the patient's urethra and into the bladder, said injection tubeassembly comprising: i. a cooling fluid inlet comprising a single tube;ii. a coaxial portion comprising:
 1. an inner coaxial tube; and,
 2. anouter coaxial tube, said inner coaxial tube and outer coaxial tube beingcoaxial, said outer coaxial tube being in fluid communication with saidcooling fluid inlet and for discharging said cooling fluid into thebladder, said inner coaxial tube for retaining a distal portion of anendoscope; and, iii. an endoscope inlet comprising a single tube, saidendoscope inlet for containing a proximal portion of an endoscope; and,iii. a connector for connecting said cooling fluid inlet, said coaxialportion and said endoscope inlet; d) delivering cooling fluid throughsaid inlet of said injection tube assembly during operation of said atleast one ablative surgical device, said cooling fluid being deliveredinto the bladder; and, e) operating said suction tube to expel bladderfluid from the bladder during said delivering of cooling fluid throughsaid injection tub assembly, said bladder fluid including said coolingfluid, wherein said urethra is cooled by said cooling fluid to preserveliving tissue thereof.
 20. The method of claim 19, further comprisingthe step of inserting an endoscope into said endoscope inlet.
 21. A heatexchange catheter for maintaining a suitable temperature of the urethraof a patient during ablative surgery, comprising: an injection tubeassembly, comprising: a) an inlet comprising a single tube for providingthe introduction of a heat exchange fluid; b) a coaxial portion,comprising: i) an inner coaxial tube; and ii) an outer coaxial tube,said inner coaxial tube and outer coaxial tube being coaxial, said outercoaxial tube being in fluid communication with said inlet and fordischarging the heat exchange fluid into the bladder, said inner coaxialtube for introducing bladder fluid from said bladder; c) an outletcomprising a single tube, said outlet being in fluid communication withsaid inner tube; and, d) a connector for connecting said inlet, saidcoaxial portion and said outlet, wherein during use, heat exchange fluidis delivered through said inlet, through said outer coaxial tube thusproviding heat transfer with said urethra, discharged to the bladder,and mixed with bladder fluid, and wherein bladder fluid is directedthrough said inner coaxial tube and through said outlet.
 22. A heatexchange catheter for maintaining a suitable temperature of the urethraof a patient during ablative surgery, comprising: an injection tubeassembly, comprising: a) a heat exchange fluid inlet comprising a singletube; b) a coaxial portion comprising: a. an inner coaxial tube; and, b.an outer coaxial tube, said inner coaxial tube and outer coaxial tubebeing coaxial, said outer coaxial tube being in fluid communication withsaid heat exchange fluid inlet and for discharging said heat exchangefluid into the bladder, said inner coaxial tube for retaining a distalportion of an endoscope; c) an endoscope inlet comprising a single tube,said endoscope inlet for containing a proximal portion of an endoscope;and, d) a connector for connecting said heat exchange fluid inlet, saidcoaxial portion and said endoscope inlet, wherein during use, heatexchange fluid is delivered through said heat exchange fluid inlet,through said outer coaxial tube, and into the bladder.
 23. A heatexchange catheter for maintaining a suitable temperature of the urethraof a patient during ablative surgery, comprising: a double lumen tubeassembly, comprising: a) an inlet comprising a single tube; b) a doublelumen portion, comprising: a first fluid passageway; and a second fluidpassageway, said first fluid passageway being in fluid communicationwith said inlet and for discharging heat exchange fluid into thebladder, said second fluid passageway for introducing bladder fluid fromsaid bladder; c) an outlet comprising a single tube, said outlet beingin communication with said second fluid passageway, wherein during use,heat exchange fluid is delivered through said inlet, through said firstfluid passageway thus providing heat transfer with said urethra,discharged to the bladder, and mixed with bladder fluid, and whereinbladder fluid is directed through said second passageway and throughsaid outlet.